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Ecology
High School Biology Class
What is Ecology?

Ecology – study of the interactions of
living organisms with one another and with
their physical environment.
The biosphere is the portion of Earth that
support life.
• air
• water
• land
Organisms are adapted to survive in the
conditions of their living & non-living
environments.
Ecosystem Terms

Biotic Factors – the living factors in an
organism’s environment

Examples:
a) animals
b) plants
c) fungi
d) protists
e) bacteria
Ecosystem Terms

Abiotic Factors – all of the physical (non-living)
aspects that belong to an organism’s environment.

Examples:
a) soil (mineral), water, wind (air)
 b) energy such as light or sound
c) climate, weather, temperature
Levels of Organization
1.
from
simplest to 2.
most 3.
complex 4.
5.
6.
Organism (individual)
Population
Biological community
Ecosystem
Biome
Biosphere
Population- individual organisms of the same
species living in the same geographic
location. ExampleA school of fish
How do available resources affect a
population?
Individual organisms must compete for food, water, mates and other
resources to survive.
Biological Community- a group of
populations that interact in the same
geographic area at the same time. Example:
Plants & animals that live in a park
Ecosystem- a biological commuinity and all
the abiotic factors that affect.
Biome- a large group of ecosystems that share
the same climate and biological communities.
All biomes form the Biosphere.

Habitat – a place
where an organism
lives.

Niche – the role an
organism has in its
environment

Community - the
groups of many
different species that
live together in a
particular habitat.
Ecology Terms
Ecological Relationships

Competition – a biological interaction that occurs
when two species attempt to use the same resource.

All organisms compete for resources in different ways.
Example:
Organisms compete
for water in the
desert. Plants
typically have
small, but very deep
root systems.
Ecological Relationships

Predation – the act of one organism
consuming another organism for food.

Example: cat (predator) mouse (prey)
Ecological Relationships

Predator – the animal being the aggressor
(the animal doing the hunting).
Predator:
Crocodile

Prey:
Turtle
Prey – the animal being the defender (the
animal that is being hunted).
Ecological Relationships

1.
2.
3.
Symbiosis – a relationship in which two
organisms live together in close
association.
3 Kinds
Mutualism
Commensalism
Parasitism
Ecological Relationships


1) Mutualism - a symbiotic relationship in which
both participating species benefit.
Example: aphids and ant colonies
Ecological Relationships

2) Commensalism - a symbiotic relationship in
which one species benefits and the other is neither
harmed nor helped.
Ex. Moss
growing on a tree
Ecological Relationships

3) Parasitism – a relationship in which one
organism benefits and another organism is
harmed

Parasite benefits; host is hurt.

Ex. Tick on a dog
Tapeworm
Principles of Ecology

Section 2- Flow of Energy in an Ecosystem
Energy Flow in Ecosystems
Autotrophs ( primary producers)- is an
organism that captures energy from
sunlight or inorganic substance to
produce food in an ecosystem.
Heterotrophs (consumer) – is an
organism that obtains energy by
consuming other organisms.
Consumer Types:
1) Herbivore – feed directly on green plants.

Examples: deer, cattle, turtles
2) Carnivore – feed on other animals.

Examples: lions, hawks, wolves
3) Omnivore – feed on plants and animals.

Examples: bears, raccoons, crayfish, humans
How do detritivores help an
ecosystem?

They decompose organic materials in an
ecosystem and return the nutrients to the
soil, air, and water.
Ex. hyenas, vultures, fungi, bacteria
What would happen to our biosphere if we
didn’t have them?
Let’s ReviewA) The primary source of energy is the sun.
B) Producers are organisms that capture light energy
and convert it into chemical energy.
C) Consumers are organisms that consume producers
or other consumers for energy.
D) Decomposers are organisms that consume
producers, consumers, and other decomposers for
energy once they have died.
Energy Flow in Ecosystems

Every living organism requires energy.

Trophic Level - shows how energy gets
transferred from organism to organism.

Sun  Producer  Consumer  Decomposer
Energy Flow in Ecosystems

Food Chain – a simple model that show
how energy flows through an ecosystem.
Food Chains:

1st level
 Producers - make their own food.

2nd level
 Herbivores - eat primary producers.

3rd level
 Carnivores - eat herbivores.
 Omnivores - eat both herbivores and carnivores.

4th level
 Decomposers - eat all dead organisms.
Energy Flow in Ecosystems

Food Web – a model that show all the
possible feeding relationships in an
ecosystem
Ecosystem Energy

The energy that is stored at each trophic level is
about 1/10 that of the level below it.

By showing the declining amounts of energy in
each of the trophic levels an ecological pyramid
can be formed.
90% of the
available
energy is used
by the
organism at
each level,
only 10% is
available to
the next level
The number decreases at each level because less energy is available to support organisms.
Biomass-total
mass of living
matter at each
trophic level.
The number
decreases at each
level because
less energy is
available to
support
organisms.
Biomagnification is the sequence
of processes in an ecosystem by
which higher concentrations of a
particular chemical, such as the
pesticide DDT, are reached in
organisms higher up the food
chain, generally through a series
of prey-predator relationships.
Principles of Ecology
Section 3-Cycling of Matter
•Anything that takes up space and has mass
•Neither created or destroyed
•Cycles within any ecosystem and is reused
•Provides the nutrients needed for organism to function – ex.
carbon, nitrogen
MATTER CYCLES WITHIN
ECOSYSTEMS
•
•
In any ecosystem, organisms obtain the matter that
they need to build their organic substance from other
organisms and from their surroundings.
Ex. Nutrients in the green grass pass to the cow that
eats the grass. The cycle continues until the last
consumer dies. Detritivores return the nutrients to the
cycle, and the process begins again.
Key Concepts

Biogeochemical cycles: the combination of
processes that exchange matter through the
biosphere.
Water Cycle, Carbon Cycle, Nitrogen Cycle
Lesson Objectives
How do nutrients move through biotic and abiotic parts of an ecosystem?
Why are nutrients important to living organisms?
What are the biogeochemical cycles of nutrients and how are they alike
http://www.css.cornell.edu/faculty/hmv1/watrshed/Etrans.htm
90% of water vapor evaporates from oceans, lakes, & rivers.
The evaporation of water from the surface of plant leaves (10%)
=
TRANSPIRATION
___________________
The return of water to
the surface in the form of
rain, snow, sleet, hail, etc.
=
PRECIPITATION
____________________
What are the carbon and oxygen cycles?
Do you remember what
happens during
photosynthesis?
CO2
Producers change ___
into glucose and
O2
release ___
.
4 main CARBON reservoirs
in BIOSPHERE
CO2 in
atmosphere
atmosphere
1. In ____________ as CO2 gas
CO2 in
Ocean
ocean as dissolved CO2 gas
2. In _______
land
3. On _______
in organisms, rocks, soil
Underground
4. ______________as coal & petroleum (fossil fuels) and calcium
BIOLOGY; Miller and Levine; Prentice Hall; 2006
carbonate in rocks
Where does CO2 in atmosphere come from?
CO2 in
atmosphere
Volcanic activity
1. ________________
CO2 in
Ocean
Human activity (burning fossil fuels)
2. ______________
Cellular respiration
3. _________________
4. Decomposition
____________ of dead organisms
BIOLOGY; Miller and Levine; Prentice Hall; 2006
WHY IS CARBON IMPORTANT?
BUILDING BLOCKS
Found in all the _____________________
of cells:
carbohydrates, proteins, nucleic acids, lipids
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
WHY IS CARBON IMPORTANT?
Carbon in CO2 provides the atoms for
GLUCOSE
PHOTOSYNTHESIS
__________ production during __________________...
the fuel that all living things depend on.
http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0076.JPG
http://www.biologyclass.net/mitochondria.jpg
NITROGEN CYCLE
Section 3-3
N2 in Atmosphere
NO3and NO2-
NH3
BIOLOGY; Miller and Levine; Prentice Hall; 2006
WHY IS NITROGEN IMPORTANT?
NITROGEN
__________________make
BASES
DNA and RNA.
Nitrogen is needed to make proteins.
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
Image by Riedell
78% of the atmosphere is made
up of NITROGEN
CAN’T use the nitrogen
BUT we _____
directly from the air.
N2 gas is captured from
the air by bacteria that
live in water, the soil, or
grow on the roots of some plants.
Image by Riedell
http://web.jjay.cuny.edu/~acarpi/NSC/12-dna.htm
_________________
Image by Riedell
The process of capturing and changing
(“fixing”) nitrogen into a form that plants
can use is called __________________.
Nitrogen Fixation
Consumers get nitrogen by eating producers
or other animals that contain nitrogen.
When animals die and decay or urinate the nitrogen
returns to the soil as ammonia. Other bacteria
NITRATES (NO3- )
in the soil convert ammonia into _____________
NITRITES (NO2-)
& _________________which
plants can also use.
The nitrogen we need for proteins, ATP, and
nucleic acids comes from
the ___________
FOOD WE EAT
___________
NOT THE AIR
we breathe!
Image from: http://www.utdallas.edu/images/departments/biology/misc/gonzalez-image.jpg
and http://www.cibike.org/CartoonEating.gif
modified by Riedell
NITROGEN CYCLE
Section 3-3
N2 in Atmosphere
NO3and NO2-
NH3
BIOLOGY; Miller and Levine; Prentice Hall; 2006
Some bacteria change nitrogen compounds
into nitrogen gas that’s released into the
atmosphere.
THIS PROCESS
IS CALLED
DENITRIFICATION
_________________
Community Ecology
Primary Succession

Begins in a place without any soil





Sides of volcanoes
Landslides
Flooding
Starts with the arrival of living things such
as lichens that do not need soil to survive
Called PIONEER SPECIES
http://botit.botany.wisc.e
du
http://www.saguaro-
Secondary Succession



Begins in a place that already has soil and
was once the home of living organisms
Occurs faster and has different pioneer
species than primary succession
Example: after forest fires
Climax Community


A stable group of plants and animals that
is the end result of the succession process
Does not always mean big trees


Grasses in prairies
Cacti in deserts
Population Dynamics
A population is a group of
organisms of the same species that
live in a specific area.
Population Distribution- can have an affect on how population is
sampled, which can affect density measurement.
Clumped most common because resources are usually clumped.
What limiting factors are density independent?
Recall that population density is the number of members of
a population per unit.
A density-independent factor is any
factor in the environment that does not
depend on population density like natural
disasters.
ex. hurricanes, oil spills
A density – dependent factor is any factor in
the environment that depends on population
density. Ex. disease, competition, parasites,
and predators.
What factors affect a population’s
growth rate?
Emigration – the number of individuals moving away from a
population.
Immigration – the number of individuals moving into a
population.
Logistic Growth
Populations cannot grow exponentially
forever. At some point, the rapidly
increasing population will strain available
resources. Logistic growth occurs when the
population’s growth slows or stops at the
population’s carrying capacity.